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Toronto, Canada

Liu Y.,Quad Engineering Inc.
Proceedings of the 10th International Conference on Steel Rolling | Year: 2010

Quad Engineering developed software to simulate the formation of ridge buckles in cold rolling. Through the simulation, it is found that the ridge buckles can be reduced thru use of upstream mill stands with higher local rigidity and/or downstream mill stand with lower local rigidity. The local rigidity of a mill stand is a new term introduced here, which denotes the capability of a mill stand to resist local work roll flattening. Further analysis shows that this finding is applicable to all shape defects in general, and the shape delects have self-cure capability, which is sensitive to local rigidities of the mill stands. The shape defects self-cure capability is another new term introduced here, which denotes the capability of the strain energy in latent shape defects tends to release itself in the subsequent rolling passes. The shape defects self-cure capability and its sensitivity to local rigidity are particularly useful in reducing ridge buckles. Based on these findings, several new methods to reduce ridge-buckles are proposed, such as using first stand of significantly higher local rigidity, using last stand of significantly lower local rigidity, and using an additional stand of veiy high local rigidity upstream of a cold mill. The effectiveness of the proposed methods is compared through simulation. Use of a skin pass mill with very high local rigidity lor flattening the ridges before cold rolling is the most effective of the proposed methods. Since the local rigidity of existing skin pass mills is similar to those of typical cold mills, they are not suitable for this application. To fulfill this new application, a new ridge flattening skin pass mill is conceptually developed. Source


Liu Y.,Quad Engineering Inc. | Liu S.,Yanshan University
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2015

A model to investigate the effects of latent shape defects (residual stress profiles or patterns) in feed stock or created in previous pass/stand on shape at mill delivery side is developed. Through the model, it is found that a major portion of the shape defects cannot pass through the roll bite and be reflected by the tension stress profiles at delivery side. Or we can say that the shape defects are "eliminated" when passing through the roll bite without any control action. We call this phenomenon the self-curability of shape defects. On the other hand, a small portion of the shape defects does pass through the roll bite and remain as the same type of shape defects at mill delivery side. This phenomenon is called explicit heritability of shape defects. A large portion of the shape defects that self-cured when passing through the roll bite actually converts into thickness variations across strip width, which can further induce the same type of shape defects if the thickness variations are corrected in subsequent passes. We call this phenomenon the implicit heritability of shape defects. This paper reveals the variations of all major process parameters when shape defects pass through the roll bite, and explains the self-curability, explicit heritability and implicit heritability of shape defects through a simulation example. © 2015 by AIST. Source


Liu Y.,Quad Engineering Inc. | Fan J.,Quad Engineering Inc. | Liu S.,Yanshan University
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2014

CFD (Computational Fluid Dynamics) models of the batch annealing furnaces were developed using ANNSYS Fluent. Different thermal conductivities in radial and axial direction of the coils were considered. The annealing process with both existing and new impellers was simulated. The results were compared to predict the heating time savings of the annealing cycle with the new impeller. Required modifications to the annealing cycles due to the new impellers were determined. The possibility of improving the current annealing practice was also determined through the simulation. © 2014 by AIST. Source


Zhang H.,Quad Engineering Inc. | Marsden K.,WHEMCO Inc. | Freborg A.,Deformation Control Technology, Inc.
Iron and Steel Technology | Year: 2013

The article illustrates the potential of this design approach by examining a compact hot strip mill equipped with continuous variable crown (CVC) roll shifting and work roll bending shape control. Conventional machine design assumptions can oversimplify roll material response to applied force distribution. Work rolls (WR) and backup rolls (BUR) designed for flat rolling service incorporate a metallurgical compromise of wear resistance and damage tolerance. Alloy solidification behavior influences both the material microstructure of the working surface that governs performance and the bulk mechanical properties within the massive component cross- sections. The backup rolls are supplied in duplex or nionobloc tool steel quality, manufactured by either casting or forging routes. In all cases, the outer working zone of a mill roll exhibits a hardened micro- structure that generates a compressive stress state on the surface. Source


Liu Y.,Quad Engineering Inc. | Zhang H.,Quad Engineering Inc. | Somers B.,Lehigh Heavy Forge | Marsden K.,WHEMCO Inc. | Freborg A.,Deformation Control Technology, Inc.
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2013

The present work began by investigating the global force distribution and inter-roll contact force distribution in CVC rolls of a compact hot strip mill with the advanced flat rolling simulation model developed by Quad Engineering. The stress fields within the work roll and backup roll were calculated using commercial FEA software for the force distributions predicted by the Quad model. Deformation Control Technologies predicted the residual stress patterns imparted by roll manufacturing, which were then superimposed onto the mechanical model to generate combined stress fields within the rolls. Fracture mechanics principles were applied to calculate the stress intensity factors associated with a hypothetical flaw in order to quantify fatigue stress response. Finally, the tolerable design flaw size criteria were mapped through the cross section of the rolls based on the calculated stress intensity distribution, incorporating the influence of a typical embedded flaw shape. Results facilitate development of specifications and inspection criteria for CVC rolls operating under real loading conditions. Source

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